Fuel control apparatus

ABSTRACT

An apparatus for controlling the fuel supply to an engine by adjustment of the control stop of a fuel injection metering pump has a three-dimensional cam whose angular and axial positions are variable in response to engine operating conditions, for example intake manifold pressure and throttle lever position. A cam follower for the three-dimensional cam in turn rotates a twodimensional cam. A further cam follower, for the two-dimensional cam, can be moved along the two-dimensional cam in response to a third engine operating condition, for example the position of the engine choke control. The resultant position of the further cam follower is transmitted to the control stop of the metering pump.

United States Patent Soltau et al.

[151 3,650,257 [451' Mar. 21, 1972 [54] FUEL CONTROL APPARATUS [21]Appl. No.: 25,228

[30] Foreign Application Priority Data Apr. 14, 1969 Great Britain..18,905/69 [5 6] References Cited 7 UNITED STATES PATENTS 2,984,2285/1961 Braun etal. ..123/140.31

3,146,770 9/1964 Garcea ..l23/l40.3l

FOREIGN PATENTS OR APPLICATIONS 1,202,171 7/1959 France ..l23/l40.3l

Primary Examiner-Laurence M. Goodridge Attorney-Holman & Stern [5 7]ABSTRACT An apparatus for controlling the fuel supply to an engine byadjustment of the control stop of a fuel injection metering pump has athree-dimensional cam whose angular and axial positions are variable inresponse to engine operating conditions, for example intake manifoldpressure and throttle lever position. A cam follower for thethree-dimensional cam in turn rotates a two-dimensional cam. A furthercam follower, for the two-dimensional cam, can be moved along thetwodimensional cam in response to a third engine operating condition,for example the position of the engine choke control. The resultantposition of the further cam follower is transmitted to the control stopof the metering pump.

13 Claims, 6 Drawing Figures PATENTEDMARm m2 SHEET 1 OF 5 IVENTOR 62m BMrim ATTORNEYS PATENTEDMAR21 I972 3,650,257

SHEET 5 [IF 5 El: ENGINE 51 /77 L. Z METERING DISTRlESUTOR 49 HATTORNEYS FUEL CONTROL APPARATUS This invention relates to apparatuswhich controls a shuttletype metering pump in a fuel injection systemfor an engine by varying the position of the control stop of the saidpump.

According to the invention an apparatus for controlling a shuttle-typemetering pump in a fuel injection system for an engine comprises athree-dimensional cam whose angular and axial positions are respectivelyalterable, in use, in accordance with first and second engine operatingconditions, a first cam follower coacting with the three-dimensionalcam, a twodimensional cam movable by the first cam follower, a secondcam follower engaging the two-dimensional cam and movable relativethereto in response to a third engine operating condition, and means fortransmitting the position of the second cam follower to a control stopon the metering pump.

An apparatus in accordance with the invention will now be described byway of example and with reference to the following drawings in which:

FIG. 1 is a section through the apparatus;

FIG. 2 is a view on the line 2-2 in FIG. 1 with part of the casingremoved for clarity;

FIG. 3 is a section on line 3-3 in FIG. 2;

FIG. 4 is a section on line 4-4 in FIG. 3;

FIG. 5 is a part view on line 55 in FIG. 2; and

FIG. 6 is a diagrammatic representation of a fuel injection systemincorporating the apparatus shown in FIGS. 1 to 5.

A casing 10 includes an end cover 11 mounted thereon by means of screw28. A diaphragm assembly 9 includes a diaphragm 12 sealingly engagedbetween the end cover 11 and the remainder of the casing 10, a dishedplate 13, a first spring locating plate 14, a clamping plate 15, and abolt 16 and nut 17 securing the assembly together.

An adjusting member 18 is threadedly engaged in the end cover 11 andsupports a second spring locating plate 19. A compression spring 27 ismounted between the plates 14, 18. The adjusting member 18 permitsvariation of the force exerted by the spring 27 for a given position ofthe diaphragm as sembly 9. A set screw 20 within the member 18 abuts theend of the bolt 16 and limits the travel in one direction of thediaphragm assembly 9. Lock nuts 21, 22 are threaded on to the member 18and set screw 20 respectively. A cap 23 is attached to the end cover 11by screws 24. The end cover 11 includes a through passage 25 in which ismounted a pipe connection 26.

The casing 10 includes an access plate 28 and a side cover 29. Withinthe casing 10 is a spindle 30 which carries a sleeve 31 rotatable onroller bearings 32. A plate 33 having an armate slot 34 is pivotallymounted on the sleeve 31 by a screw 35 to provide a crank arm for thesleeve 31. A screw 36 engages the sleeve 31 through the slot 34 to lockthe plate 33 in a desired angular position relative to the sleeve 31. Apair of links 37 each have one end pivotally mounted on the plate 33 andthe other end pivotally engaged with an eye bolt 38 threadedly mountedin the bolt 16. A compound surface cam 39 has bearing rings 40 mountedtherein, the rings 40 being slidable on the sleeve 31. The cam 39carries a set screw 41 one end of which engages an axial slot 42 in thesleeve 31 so as to allow axial movement but to prevent rotation betweenthe sleeve 31 and the cam 39. A locknut 43 is threaded on the set screw41. The cam 39 has two flanges 44, 45 in spaced parallel relationshipand having engaged therebetween a pin 46 carried at one end of an arm 47which is rotatable by a shaft 48 journaled in the casing 10. The shaft48 carries, externally of the casing 10, a lever 49 rotatable between apair of substantially identical adjustable stops 50, 51.

A first cam follower 52 is supported on a spindle 53 journaled in thecasing 10. Integral with the cam follower 52 is a bracket 54 on which acam plate 55 is rotatably mounted about a pin 56 and secured by screws57, 58, whereby adjustment of the position of the cam plate 55 withrespect to the bracket 54 may be effected. A spindle 59 journaled in thecasing 10 is rotatable by means of an arm 60 biased in one direction bya spring 61 and urged in the other direction by a cam 62 coacting withadjustable screw 63 and which is itself rotatable by means of anintegral arm 64 against a torsion spring 65.

The spindle 59 supports a bracketed arm 66 on which is mounted a pivot67. The bracket 66 and pivot 67 respectively abut screw stops 68, 69 atcorresponding extremities of rota tion of the spindle 59. A second camfollower 8, rotatable about the pivot 67 comprises a pair of arms 70, 71maintained in spaced parallel relationship by a pair of domed studs 72,73 which engage opposite sides of the cam plate 55 and a flanged roller74 rotatably mounted between the arms 70, 71 and intermediate theirends.

The roller 74 bears upon an edge of the cam plate 55 and also upon apiston-like member 75 slidably mounted in the casing 10, and biased byexternal means (not shown) against the roller 74. The casing 10 includesan upstanding portion 76 which supports a shuttle-type metering pump 77associated with a fuel-injection system for an engine and having acontrol stop 77a. A diaphragm seal 78 extends between the casing portion76 and the member 75. The casing 10 also includes a port 79.

In use the pipe connection 26 is coupled to the inlet manifold of theassociated engine downstream of the throttle 80 in the air intake 81 andthe port 79 is open to atmospheric pressure. Pressure drop in the saidmanifold urges the diaphragm assembly 9 against the spring 27 androtates the cam 39, via the links 37, plate 33, sleeve 31 and set screw41, in a direction tending to result in an anticlockwise rotation of thefirst cam follower 52, as seen in FIG. 1.

The lever 49 is connected to the throttle control 84 of the associatedengine in such a way that movement of the said throttle control toaccelerate the engine moves the cam 39 axially, via the shaft 48, arm 49and roller 46, in a direction tending to result in clockwise rotation ofthe first cam follower 52, as seen in FIG. 1.

The lever 64 is connected to the choke control 83 of the engine in sucha way that movement of the choke to the engine starting position causesthe cam 62 to rotate the lever 60 against the spring 61 and thereby torotate the bracket 66 clockwise as seen in FIG. 1.

The member 75 coacts with the control stop 77a of the shuttle-typemetering pump 77, whereby downward movement of the member 75 permitsincreased movement of the shuttle and hence increased fuel delivery tothe injectors 82.

The angular position of the first cam follower 52 is transmitted to thecam plate 55 via the bracket 54. The position of the second cam follower8 with respect to the cam plate 55 depends on the angular position ofthe bracket 66, and hence on the position of the choke. The position ofthe roller 74, and hence that of the member 75, depends therefore on thepositions of the throttle and choke controls and the pressure in theengine inlet manifold.

For a given initial manifold pressure and choke positions, movement ofthe throttle to accelerate the engine will cause the second cam followerto rotate anticlockwise as seen in FIG. 1, and thereby cause the pump 77to increase fuel delivery and so permit increase of the engine speed.The resulting variations in pressure in the inlet manifold causeadjustment of the position of the diaphragm assembly 9, and thereby alsocause adjustment of the fuel delivery. An equilibrium condition will bereached for any throttle position when the force exerted on thediaphragm assembly 9 by the manifold pressure drop is equal to the forceexerted by the spring 27. For any throttle position and manifoldpressure there will therefore be a corresponding fuel delivery.

Operation of the choke control, resulting in clockwise rotation of thebracket 66, as seen in FIG. 1, results in a considerably increased fueldelivery for all positions of the throttle control and the manifoldpressure drop.

The screw stop 68 limits the anticlockwise rotation of the bracket 66,as seen in FIG. 1, and hence limits the movement of the cam follower 8in a direction which will urge the member 75 towards the pump 77, andthereby reduce fuel delivery. The screw stop 68 may therefore be used toadjust a minimum fuel delivery for slow running of the engine.

In an alternative method of use, the diaphragm assembly 9 may be maderesponsive to a pressure signal derived from the engine speed. Therewill in this case, for any combination of throttle position and enginespeed, be a unique corresponding fuel delivery.

Having thus claimed our invention what we claim as new and desire tosecure by Letters Patent is:

1. ln a fuel injection system of an internal combustion engine, ashuttle-type metering distributor for fuel having a control stopdetermining the fuel injection dosage and apparatus for controlling theposition of said control stop comprising a housing, a compound surfacecam, means mounting said compound surface cam for independent movementangularly about an axis and axially relative to the housing, meanssensitive to a first engine operating condition displacing said compoundsurface cam angularly, means sensitive to a second engine operatingcondition displacing said compound surface cam axially, a first camfollower coacting with said compound surface cam, a cam plate movablymounted in the housing and coupled to the first cam follower fordisplacement relative to the housing thereby, a second cam followerengaging the cam plate mounted for movement in one direction by the camplate and also movable in a transverse direction means sensitive to athird engine operating condition moving said second cam follower intransverse direction, and means displacing said control stop inaccordance with the displacement of the second cam follower in said onedirection.

2. An apparatus as claimed in claim 1 in which said means sensitive to afirst engine operating condition comprises a diaphragm responsive to apressure in an air intake manifold of the engine and operativelyconnected to the compound surface cam.

3. An apparatus as claimed in claim 2 which includes a sleeve upon whichthe compound surface cam is axially slidable, means for preventingrelative angular movement between the sleeve and the compound surfacecam, a crank element mounted on the sleeve and a link connecting thecrank element to the diaphragm.

4. An apparatus as claimed in claim 3 which includes means for adjustingthe relative angular positions of the crank element and the sleeve.

5. An apparatus as claimed in claim 4 which includes means for adjustingthe relative positions of the diaphragm and the link.

6. An apparatus as claimed in claim 2 which includes a spring biasingthe diaphragm against movement due to decrease in the pressure in theengine intake manifold.

7. An apparatus as claimed in claim 6 which includes means for varyingthe bias applied by the spring.

8. An apparatus as claimed in claim 2 which includes means for limitingmovement of the diaphragm in response to a decrease in pressure at theengine intake manifold.

9. An apparatus as claimed in claim 3 in which said means sensitive to asecond engine operating condition comprises a lever movable in responseto the position of a throttle control for the engine and operativelyconnected to the compound surface cam.

10. An apparatus as claimed in claim 1 in which said means mounting saidcompound surface cam comprises a sleeve mounted for rotation about itsaxis and slidably supporting the compound surface cam, and means forpreventing relative rotation between the sleeve and the compound surfacecam, said means sensitive to a first engine operating conditioncomprises a diaphragm responsive to the pressure in an intake manifoldof the engine and operatively connected to the sleeve, and said meanssensitive to a second engine operating condition comprises a leverresponsive to the position of a throttle control for the engine andoperatively connected to the compound surface cam to move the latterrelative to the sleeve.

11. An apparatus as claimed in claim 1 further comprising meanspivotally mounting the cam plate, the cam plate being rotatable aboutsaid mounting means b the firstcam follower. 12. An apparatus as claimedm cam 11 in which said means sensitive to a third engine operatingcondition comprises a lever movable in response to the position of achoke control for the engine and operatively connected to the second camfollower to move the latter in said transverse direction which istransverse to the axis of said means pivotally mounting the cam plate.

13. An apparatus as claimed in claim 12 in which the means displacingthe control stop comprises a piston member slidably mounted in thehousing, engaging the second cam follower and operatively connected tothe control stop, the piston being movable in a direction transverseboth to the axis of said pivotal mounting means and to the direction ofmovement of the second cam follower by the choke control.

1. In a fuel injection system of an internal combustion engine, ashuttle-type metering distributor for fuel having a control stopdetermining the fuel injection dosage and apparatus for controlling theposition of said control stop comprising a housing, a compound surfacecam, means mounting said compound surface cam for independent movementangularly about an axis and axially relative to the housing, meanssensitive to a first engine operating condition displacing said compoundsurface cam angularly, means sensitive to a second engine operatingcondition displacing said compound surface cam axially, a first camfollower coacting with said compound surface cam, a cam plate movablymounted in the housing and coupled to the first cam follower fordisplacement relative to the housing thereby, a second cam followerengaging the cam plate mounted for movement in one direction by the camplate and also movable in a transverse direction means sensitive to athird engine operating condition moving said second cam follower intransverse direction, and means displacing said control stop inaccordance with the displacement of the second cam follower in said onedirection.
 2. An apparatus as claimed in claim 1 in which said meanssensitive to a first engine operating condition comprises a diaphragmresponsive to a pressure in an air intake manifold of the engine andoperatively connected to the compound surface cam.
 3. An apparatus asclaimed in claim 2 which includes a sleeve upon which the compoundsurface cam is axially slidable, means for preventing relative angularmovement between the sleeve and the compound surface cam, a crankelement mounted on the sleeve and a link connecting the crank element tothe diaphragm.
 4. An apparatus as claimed in claim 3 which includesmeans for adjusting the relative angular positions of the crank elementand the sleeve.
 5. An apparatuS as claimed in claim 4 which includesmeans for adjusting the relative positions of the diaphragm and thelink.
 6. An apparatus as claimed in claim 2 which includes a springbiasing the diaphragm against movement due to decrease in the pressurein the engine intake manifold.
 7. An apparatus as claimed in claim 6which includes means for varying the bias applied by the spring.
 8. Anapparatus as claimed in claim 2 which includes means for limitingmovement of the diaphragm in response to a decrease in pressure at theengine intake manifold.
 9. An apparatus as claimed in claim 3 in whichsaid means sensitive to a second engine operating condition comprises alever movable in response to the position of a throttle control for theengine and operatively connected to the compound surface cam.
 10. Anapparatus as claimed in claim 1 in which said means mounting saidcompound surface cam comprises a sleeve mounted for rotation about itsaxis and slidably supporting the compound surface cam, and means forpreventing relative rotation between the sleeve and the compound surfacecam, said means sensitive to a first engine operating conditioncomprises a diaphragm responsive to the pressure in an intake manifoldof the engine and operatively connected to the sleeve, and said meanssensitive to a second engine operating condition comprises a leverresponsive to the position of a throttle control for the engine andoperatively connected to the compound surface cam to move the latterrelative to the sleeve.
 11. An apparatus as claimed in claim 1 furthercomprising means pivotally mounting the cam plate, the cam plate beingrotatable about said mounting means by the first cam follower.
 12. Anapparatus as claimed in claim 11 in which said means sensitive to athird engine operating condition comprises a lever movable in responseto the position of a choke control for the engine and operativelyconnected to the second cam follower to move the latter in saidtransverse direction which is transverse to the axis of said meanspivotally mounting the cam plate.
 13. An apparatus as claimed in claim12 in which the means displacing the control stop comprises a pistonmember slidably mounted in the housing, engaging the second cam followerand operatively connected to the control stop, the piston being movablein a direction transverse both to the axis of said pivotal mountingmeans and to the direction of movement of the second cam follower by thechoke control.